To lovers of the world's most odoriferous fruit, something doesn't smell right in Thailand's durian country, where a fruit breeder with the Horticulture Research Institute is in the midst of creating a line of durian varieties that lacks what some say is the most intriguing aspect of this large and spiky, creamy-fleshed tree fruit — its smell.

Dr. Songpol Somsri has spent 25 years trying to eliminate the durian fruit's renowned gym socks-and-gasoline stench. He has crossed 90-plus durian varieties and, with a discerning nose, selected their offspring. Generation by generation, he has bred away the odor. And he thinks he's close to putting it on the market.

When NPR last checked in with scientist Songpol Somsri, back in 2007, he had just introduced the first deodorized durian, called the Chantaburi No. 1. This year, he has released his fourth, fifth and sixth such durians, and he says he has more in the works.

Songpol says his durians, which could be available in shops in Southeast Asia in just another season or two, will be marketed toward consumers uneasy about eating the more pungent durian varieties. Already, taste tests for small groups of visitors to Songpol's experimental orchard have produced positive reviews, he says.

But a proper durian smells like "heaven and hell", as a Mother Jones reporter put it. To aficionados of the fruit, who find the aroma wildly intoxicating, Songpol's durians stink. Joe Real, a Philippines native and tropical fruit expert with the California Rare Fruit Growers, isn't impressed by what he's heard of Songpol's creations.

"If you remove the smell of the durian just because some people don't like it, you also remove the fun and the excitement," says Real, who has made durian wine and plans to market the product in California at his yet-to-be-launched Amrita Winery.

Real says that the smell of a durian enhances its taste — and to lose the one is to offset the other.

"The smell works hand-in-hand with the flavor," he says. "Without the smell, the durian loses its potency."

Sensory experts call this taste-smell chemistry "retro-nasal olfaction," the physiological process by which we actually smell a bite of food even after it's entered our mouths. Pinch your nose during dinner, they tell us, and the joy of eating will nearly vanish.

But Songpol says the smell is not gone from his special varieties — just reduced. Anyway, he didn't create his new durians for aficionados.

"These durians are for people who don't like the smell or haven't had durian before," he says. "This will create a new market. The old market will not go away."

Still, other durian experts are nervous. Mark "Birdee" Léger, a French expat who lives on a durian orchard in southern Thailand, fears that commercial breeding projects are, generation by generation, robbing the durian of its finest attributes, producing tame and innocuous varieties suitable for the commercial market, while older heritage trees slip to the wayside — think potatoes, corn, watermelons, tomatoes and apples.

Léger says the very best durians come from wild specimens that sprouted from seed and have never been cultivated, and he considers projects like Songpol's to be "an insult to the purity of things such as nature offers us."

Real doesn't believe Songpol's Chantaburi series has the bite to influence the durian market.

"As long as Asian immigration continues around the world, people everywhere will know what a good durian is, and they won't want them without the smell," he explains.

The flipside of turning durian and other foods into more marketable versions of themselves is that they often become more durable, and able to withstand the rigors of transportation. In the case of durians, it's the smell that's limited their travel.

Songpol expects that Southeast Asian airlines and municipal transportation systems that currently forbid carriage of durians because of their smell will make exceptions for his Chantaburi series. Meanwhile, about 20,000 sapling trees which Songpol has sold to farmers around Thailand will start bearing sizeable crops by 2013 or 2014, he says. Eventually, the fruits might be exported into durian-dubious markets overseas, Songpol says, though when the Chantaburi series may reach American shores is uncertain.